A vehicle air-conditioning seat having a blower and a heater therein is disclosed in JP-A-2003-237354, for example. In JP-A-2003-237354, an electric heater and a blowing unit are incorporated in the interior of a seat back and a seat cushion, respectively. A seat cover can be heated by the electric heater, and at the same time, the blowing air of the blowing unit can be blown-out from a blow-out opening provided in the seat cover. At this time, in order to prevent an occupant from feeling that the seat is too hot or too cold by the vehicle cabin environment, a heating amount by the electric heater and a blowing amount from the blowing unit can be respectively adjusted by one operation means.
That is, the vehicle air-conditioning seat disclosed in JP-A-2003-237354 basically has two modes of a cool mode mainly using the blowing unit and a heat mode mainly using the electric heater. In addition, in order to prevent superheating or supercooling in each mode, the blowing unit or the electric heater is auxiliarily used in combination, as necessary. In JP-A-2003-237354, the temperature in the entire surface of the seat cushion and the seat back is uniformly adjusted.
In this kind of vehicle air-conditioning seat, the cool mode is used in summer and the heat mode is used in winter. The vehicle air-conditioning seat is hardly used in spring or autumn. When the vehicle air-conditioning seat is used in spring or autumn, an occupant's body becomes too cold or stuffy, thereby causing discomfort. In JP-A-2003-237354, the supercooling in the cool mode and the superheating in the heat mode can be avoided depending on the vehicle cabin environment. However, JP-A-2003-237354 does not go beyond the range of the cool mode and the heat mode, and hence, the vehicle air-conditioning seat is assumed to be hardly used in spring or autumn. Accordingly, the advantage of mounting the vehicle air-conditioning seat cannot be sufficiently utilized.